Tuning arrangement for radio receiving sets



Jan. 21, 1936. v D CQLLINS 2,028,137

TUNING ARRANGEMENT FOR RADIO RECEIVING SET-S Filed Oct. 24, 1934 INVENTOR V1292! Z7. Chili/2,5

ATTORN EYS Patented Jan. 21, 1936 PATENT OFFICE TUNING ARRANGEMENT FOR RADIO RECEIVING SETS Virgil D. Collins, Colwick, N. J.

Application October 24, 1934, Serial No. 749,747

5 Claims. (01. 116--124.4)

The present invention relates to tuning receiversand it particularly relates to improved device for enabling selective tuning of any desired stations.

In the reception of radio broadcasts, one general type of radio receiving set is provided with a tuning dial or indicator which is connected to a variable condenser,the variation of the capacity enabling thereceivingcircuit of the radio set to be brought in resonance with the incoming signal. The dials enabling visual control of the tuning usually include needles or hair lines, passing over a scale graduated in terms of frequency and/or wave length, such needle or hair line being connected to the condenser shaft, which is driven from the manual turning knob or control. By-adjusting the turning knob or control it is possible to tune in the various broadcasting stations, the dial during this tuning operation indicating the frequency and/or wave length.

In radio broadcasting the sending or transmitting stations are generally limited to certain defined bands of frequency and wave length. and

the various individual stations are specifically limited to certain values in this particular band. For example, the international agreement between the various nations limits the broadcasting stations in the 11 meter band to a frequency range of from 25,600 k. c. to 26,600 k. 0., an interval of 1,000 k. c.

Within this limited band it is desirable to space the broadcasting stations suificiently apart so that each station may be readily tuned in by the radio receiver without difficulty, but at the same time, due to the demand for broadcasting facilities, it is necessary to place the stations as closely together as possible.

For example, frequency of assignments to the various stations may be spaced apart by 10 k. c. with the result that one hundred stations may. operate in the above-described band of 1,000 k. c.

However, on most radio receivers this will only permit of an average space on the tuning scale of about I; inch in which distance the entire 100 stations fall and this close spacing causes considerable dificulty when the operator of the radio receiving set attempts to tune the set to any desired frequency or station.

This increased difficulty is due to the fact that with shorter wave length and higher frequency less variation in capacity is required in the tuning of the receiving circuit to signals of nearly the same wave length and consequently the tuning knob or control which drivesthe rotors of the variable tuning condensers need be shifted through only a minute range of movement to cover a. large number of stations.

Due to this difficulty it is impossible in many instances to use existing types of tuning systems for the tuning of the high frequencies, since with such higher frequencies there is not adequate visual separation of the stations as far as the dial of the tuning device is concerned.

To overcome these difliculties, various types of Vernier arrangements have been proposed, in which the main indicating device may be turned to approximately the position in which the incoming signals are tuned with the radio receiving circuit, the Vernier arrangement having a much greater relative movement per unit wave length or per unit frequency than the main indicating, device.

In one type of device of this character a main tuning needle having a low ratio of angular movement to the turning condenser shaft is supplemented by a Vernier tuning needle having a much higher ratio of angular movement to the condenser shaft.

In using this device the main tuning needle is brought in the position on the fixed scale over which it is rotated to the approximate vicinity of the frequency which it is desired to tune. The Vernier needle rotates simultaneously with the coarse tuning needle. When the station has been roughly tuned then a mechanism is provided by means of which the Vernier and main needles may be rotated together but at a much higher rate of angular turn, the Vernier needle then rotating over a circular Vernier scale which is generally arbitrarily graduated from zero to one hundred.

In tuning in this manner therefore, the desired frequency of thestation is initially tuned through the process of trial and error, and the corresponding position of the Vernier needle is then employed as a reference point in logging the station, and this corresponding position of the vernier needle must be separately recorded by the operator if he desires to tune in the station at a future date by directly tuning to the fixed reference points so obtained.

' Although these vernier tuning devices may be applied, if desired, to a circular ribbon or band type of tuning scale, this creates considerable difiiculty due-to the inability to see at a glance the entire frequency range of the tuning scaleso as to readily permit orientation in the tuning operation.

Moreover, limitations of space inherent in the dial type of tuningscale results in a complicated appearance of the dial face with a multiplicity of scales beyond those absolutely necessary for the operation of the receiver, and these considerations have rendered the provision of a separate Vernier scale for each of the high frequency bands most commonly used and desired by the'operator impractical.

An object of the present invention is to provide an improved visual indicator and manually controlled tuning arrangement for radio receiving sets, which may without difficulty and by relatively simple manipulations be tuned directlyto the frequency desired by a relatively inexpensive mechanism, which is durable and not readily derangeable during the life of the radio receiving set.

Another object is to provide a visual indicator and manual control for tuning a radio receiving set, in which, although main and vernierscales and tuning devices are employed, it will be possible' to provide indicator dial arrangements, the

visible faces of which will be simple and uncomplicated in appearance and in which a: very exact Vernier adjustment to exactly the wave length or frequency desired may be attained by Vernier 'scales correspondingly graduated toanenhanced ing-to which thehome user of "the radio-set may most readily set the needle or other indicator at the exact point'on the scale which corresponds to the transmitting frequency of the desired station; said scale being so arranged that the individual frequencies and the broadcast bands are instantly'discernible ata glanceand so spaced as to render setting of the indicator-or -needle a most convenient operation without visual and/or manual difliculty, or without necessity-of'interpolationon the part oftheuser the-need of log- 'ging from anarbitrary scale and/or meddling or manual operations of a similar character beyond the pale-of good commercial practiceand sales value.

According to one form of the invention shown upon-the accompanying drawing, the-mainand vernier scales are substantially fixed in position and-are appliedon transparent material, which may be illuminated from the interior of the de-' vice. Upon this main fixed scale is positioned the main scale, a main Vernier scale, if desired, graduated in some arbitrary manner different than the graduation of the main scale, and interiorly and/or parallel with respect to the main scale and/ or the main Vernier scale are provided with a series of short Vernier scales. On these short Vernier scales the length of the arc will be many times the length of the arc on the main scale ratios, for example, of 50 to- 1 being employed if desired.

Preferably the moving Vernier dial carrying said Vernier scales is positioned in front of the main fixed dial and in front of all these dials is positioned a dial with a series of spaced openings, the principal openings uncovering the main scale and/or the main Vernier scale, if such a scaleis employed. A central segmental opening may also be provided exposing a sufficient depth from the center to the outside so that a window on the inside main fixed dial may come opposite saidsegmental opening and permit illumination of the Vernier scale corresponding to the portion of the main scale the indicator is traversing.

The outside dial carrying the openings exposing the inside fixed dial and the intermediate Vernier dial may be turned on one shaft, while the intermediate dial is turned on another shaft.

22 of Fig. 1.

Fig, 3 is -a front view of the main fixed dial illustrating the scale and windows thereupon,

Fig.4 is a front view of the intermediate Vernier dial, and

Fig. 5 is a modification illustrating using a different vernier arrangement, illustrating how different turning ratios between the main and radio dial may be conveniently combined upon the same dial structure without an increase in the number of dials.

Referring to Fig. 2, the radio set is provided with a front panel H! which is provided with an opening H, receiving the main tuning dial l2, behind which main tuning dial is the intermediate Vernier dial i3 and the rearmost fixed main scale 14.

The main tuning dial I2 is fixed to the shaft 15 so as to'turn'therewith whilethe Vernier dial [3 is fixed to the" annulus 1 5, the shafts I5, 16 being respectively connected to thegear wheel l'l' and the' pinion' l8. The gear' wheel ll and the-pinion 18 are respectivelymeshedwith and driven=by thegear wheels l9 and Edasindicated at-'2 5 andI2B;-'which are keyed at 2| to the shaft 22.

' Theshaf t '22 iwhi'clr-carries or directly actuates in-- any standard orconventional fashion the rotors of the tuning condensers (not shown), has a bearing at 23 inthe frontpanel it and it isprovided at'its-forward end with the manually controlled knob 24.

The main dial l2 isprovided with the arcuate openings 2?- in Fig. 1, which are provided with transparent material 28, said arcuate'openings exposing the major portion of the graduations '29 and 3B, which respectively indicate the wave length and kilocycles of the stations-being tuned. Between two of the arcuate openings El, as indicatedat theupper portion of 'Fig. 1, is provided a triangular opening 3l provided with the hair line Bil, the pointSZ of which openingfalls upon the outer circle or graduations 29, indicating the wave length of the signal being tuned.

The base 33 of the triangle uncovers the innermost graduationstfl and also uncovers the circular graduations 34 .on the outside of the Vernier dial 13, the graduated circle 34 being permissibly omitted, if desired, and being desirably graduated if used in substantially from 1 to 100 or in some other arbitrary manner different than the wave length or frequency graduations of the scales 29 and 30.

Below the triangular opening 2! is the trapezoidal-opening 35 which uncovers a segment of the intermediate Vernier dial l3 and is'of sufii- Jcientdepth andwidthto singly uncover the win- (see Fig.T 2) whichis 'centrallyrprovidedwith .the graduatinglline 42 .(see' *Fig. 13)

The-Windows: 36, 31,: 38, 39 and "40 correspond respectivelyandsare,adapted'to uncoverthe arcuate vernier scales 43, 44, 45,43 andl41 onthe intermediateidial 14, when theapex'32 of .the

triangular opening 3| 'isrin'the band of frequencies which correspond to: the verniergraduations of the respective vernier scales 43 to 41.

The frame 48 of the radio :receiver ;is adapted tosupport one. or more, lamps or other illuminating devices 49, which arepositionedrin such a -manneras toilluminateasmuch as'of the trans- "parent outer. annular portion'50 of the mainfixed dial I4 as will .be exposedf'through the openings .21, 311 and '35. A triangularopening 5i isalso preferably provided. on the mainrtuning pdial I 2 directly opposite the indicator triangular opening 21. .The inner portion of themain fixed. dial l4 insidethe circle 52, as shown upon Fig. 2, is not transparent except for the windows 36 to 40,

.indicated in Figs. 1 and "3.

The intermediate dial 13, which carries the outermost vernieriscale' 34 and also the other vernier -material.so that portions of it over the windows 361to.4ll will be illuminated by the lamp 49, and will be observed when said windows 36 to 40 respectivelyareexposed by the wedge-shaped window 35 on the main turning l2.

The operation of the device is as follows:

As the knob 24 is turned, the dial I2 will be turned at a relatively slow rate by inter-meshing of the gears I1 and I9 at 25, while the intermediate dial I3 will be turned at a relatively rapid rate, say at a ratio of 50 to 1 by the inter-meshing gear andpinion 20 and 18. The outside main graduated circle 29 will be provided with a series of distinctively. designated band portions 53,54, 55, 56 and 51.

When the pointer 32 comes into the range of these distinctively marked bands, such as 53 to 51 in Fig. 1, the vernier l3 will have been turned to such a position in respect to the main dial 12 that the respective windows 36 to 40 will permit illumination of the respective vernier scales 43 to 41. Only the vernier scale corresponding to the particular band53 to 51 will be illuminated and capable of visual observation during the turning of the main graduations across the triangular opening pointer 3|.

In this manner not only is the operator of the set capable of observing substantially the entire circular scales 29 and 30, respectively indicating the wave length and frequency, as they are illuminated by the lamps or other source of illumination 49, but in addition it is possible to immediately, Without difficulty and without searching, find the particular band 53 to 51 which is being sought, and then within said band immediately tune to the exact station by the vernier corresponding scale 43 to 41 illuminated through the windows 36 to 40.

For example, as shown in Fig. 1, the pointer 32 is in the band 53 corresponding to 49 meters wave band, and although the pointer 32 moves very slowly over this band and cannot be readily adjusted thereupon, the corresponding vernier scale 45 will be exposed at the same time and will permit exactitude of tuning, since it will turn fifty times as long an are as will the pointer 32 -in-i passingziover :the them '49. The same :is true '1 for .the. other vernier-scales 43 to 41.

.:In Fig. '5 is shown an: alternative arrangement in which ,even 1 greater ranges oftfrequencies .may.fbexaconveniently. tuned :than. iS'lDOSSiblG on 5 .the idialrshownin-Figs. 1 m4.

InEFig15-similarly functioning elements to Figs. 1' 7054,5318 indicatediby. the same numerals primed.

In :this embodiment of Fig. 5 1 where the .fre-

quency becomes very-high and :the wave length 0 very. :short,. any :standard or conventional gearing arrangement .(not shown) may be provided to .changethe ratio between the vernier; shaft and :theximain shafts. I5;:and I6 with theresult that zthex amount of'rrotation of the vernier shaft= per :uriitlgraduation,swhether in wave length orfre- *rateeandimmediateztuning of the radio receiver to ;any desired stationain Wave length or frequency without the necessity of -minute or difficult.:adjustments, without the necessity 'of interpolation, logging from an arbitrary scale or other mental or manual operation of .a similar character beyond the pale of good commercial practice and sales value.

a The visual facegofcthe dial is simple andzuncomplicated and the user ofthe radio set may set his needle or other indicator on the exact point on the scale which corresponds to the transmitted frequency of the desired station.

It is also apparent that the scale is arranged I so that the individual frequencies in any of the broadcast bands may be instantly discernible at a glance and the graduations on the main and vernier scales are so spaced as to render the setting of the indicator or needle an easy operation.

While certain of the claims specify a scale graduated in terms of wave length, it is of course understood that it is within the scope of the invention and within the spirit of the claims to graduate these scales in terms of frequency.

Having thus described my invention. 'what I claim as new and desire to secure by Letters Patent is:-

1. In a radio receiver set, a visual indicating 50 and operator controllable tuning installation comprising a main scale, a vernier scale and a pointer arrangement for indicating the wave length of the station to be or which has been tuned, said main scale and vernier scale being 55 graduated in the same units, and said vernier scale including a plurality of sub-scales so graduated, each of said sub-scales corresponding to a range of wave length on the main scale and said vernier scale being connected to said main 0 scale so that the pointer arrangement will relatively move over said vernier scale a much greater distance for each unit movement over the main scale.

2. In a radio receiver set, a visual indicating 65 and operator controllable tuning installation comprising a main scale, a vernier scale and a pointer arrangement for indicating the wave length of the station to be or which has been tuned, said main scale and vernier scale being 70 graduated in the same units, and said vernier scale including a plurality of sub-scales so graduated, each of said sub-scales corresponding to a range of wave length on the main scale and said vernier scale being connected to said main scale so that the pointer arrangement will relatively move over said vernier scale a much greater distance for each unit movement over the main scale, said main scale, vernier scale and pointer arrangement taking the form of a plurality of superimposed dials, one of which is fixed and two of which are rotatable at a predetermined rate in respect to each other, said scales including circular graduations positioned concentrically in non-overlapping relationship.

3. In a radio receiver set, a visual indicating and operator controllable tuning installation comprising a main scale, a Vernier scale and a pointer arrangement for indicating the wave length of the station to be or which has been tuned, said main scale and Vernier scale being graduated in the same units, and said Vernier scale including a plurality of sub-scales so graduated, each of said sub-scales corresponding to a range of'wave length on the main scale and said Vernier scale being connected tosaid main scale so that the pointer arrangement will relapointer arrangement.

4. In a radio receiver set, a visual indicating and operator controllable tuning installation comprising a main scale, a Vernier scale and a pointer arrangement for indicating the wave length of the station to be or which has been tuned, said main scale and Vernier scale being graduated in the same units, and said Vernier scale including a plurality of sub-scales so gradf.

uated, each of said sub-scales corresponding to a range of wave length on the main scale and said Vernier scale being connected to said main scale so that the pointer arrangement will relatively move over said Vernier scale a much greater distance for each unit movement over the main scale, said main scale being fixed and carrying an illuminated transparent element graduated in wave length and also carrying a plurality of radially spaced windows, each of said windows corresponding to a sub-scale, said pointer arrangement being provided with means to cover all of said windows except the one corresponding to the portion of the main scale being traversed by the pointer arrangement.

5. In a Vernier indicating arrangement for radio receiver sets, a plurality of series of parallel graduations, a main scale for carrying some of these graduations, a Vernier scale for carrying other of these graduations, each series on the Vernier scale corresponding to a limited range on the main scale, an indicator moving relatively over said main scale and means for exposing the particular vernier scale corresponding to the portion of the main scale which the indicator is traversing.

VIRGIL D. COLLINS. 

